[GIT PULL] Please pull NFS client updates for Linux 6.19

[GIT PULL] Please pull NFS client updates for Linux 6.19

[Trond Myklebust]

Hi Linus,

The following changes since commit 6a23ae0a96a600d1d12557add110e0bb6e32730c:

  Linux 6.18-rc6 (2025-11-16 14:25:38 -0800)

are available in the Git repository at:

  git://git.linux-nfs.org/projects/trondmy/linux-nfs.git tags/nfs-for-6.19-1

for you to fetch changes up to bd3b04b46c7a9940989ff4b29376e899e93d3a4a:

  NFSv4: Handle NFS4ERR_NOTSUPP errors for directory delegations (2025-12-05 19:34:29 -0500)

Cheers
  Trond

----------------------------------------------------------------
NFS client updates for Linux 6.19

Highlights include:

Bugfixes:
- Fix 'nlink' attribute update races when unlinking a file.
- Add missing initialisers for the directory verifier in various places.
- Don't regress the NFSv4 open state due to misordered racing replies.
- Ensure the NFSv4.x callback server uses the correct transport
  connection.
- Fix potential use-after-free races when shutting down the NFSv4.x
  callback server.
- Fix a pNFS layout commit crash.
- Assorted fixes to ensure correct propagation of mount options when the
  client crosses a filesystem boundary and triggers the VFS automount
  code.
- More localio fixes.

Features and cleanups:
- Add initial support for basic directory delegations.
- SunRPC back channel code cleanups.

----------------------------------------------------------------
Anna Schumaker (5):
      NFS: Add support for sending GDD_GETATTR
      NFS: Request a directory delegation on ACCESS, CREATE, and UNLINK
      NFS: Request a directory delegation during RENAME
      NFS: Shortcut lookup revalidations if we have a directory delegation
      NFS: Add a module option to disable directory delegations

Jonathan Curley (1):
      NFSv4/pNFS: Clear NFS_INO_LAYOUTCOMMIT in pnfs_mark_layout_stateid_invalid

Mike Snitzer (2):
      nfs/localio: remove alignment size checking in nfs_is_local_dio_possible
      nfs/localio: remove 61 byte hole from needless ____cacheline_aligned

Olga Kornievskaia (4):
      NFSv4.1: pass transport for callback shutdown
      SUNRPC: cleanup common code in backchannel request
      SUNRPC: new helper function for stopping backchannel server
      NFSv4.1: protect destroying and nullifying bc_serv structure

Scott Mayhew (1):
      NFSv4: ensure the open stateid seqid doesn't go backwards

Trond Myklebust (11):
      NFS: Avoid changing nlink when file removes and attribute updates race
      NFS: Initialise verifiers for visible dentries in readdir and lookup
      NFS: Initialise verifiers for visible dentries in nfs_atomic_open()
      NFS: Initialise verifiers for visible dentries in _nfs4_open_and_get_state
      Revert "nfs: ignore SB_RDONLY when remounting nfs"
      Revert "nfs: clear SB_RDONLY before getting superblock"
      Revert "nfs: ignore SB_RDONLY when mounting nfs"
      NFS: Automounted filesystems should inherit ro,noexec,nodev,sync flags
      NFS: Fix inheritance of the block sizes when automounting
      NFS: Fix up the automount fs_context to use the correct cred
      NFSv4: Handle NFS4ERR_NOTSUPP errors for directory delegations

 fs/nfs/callback.c                 |   4 +-
 fs/nfs/callback.h                 |   3 +-
 fs/nfs/client.c                   |  21 ++++++--
 fs/nfs/delegation.c               |   8 +++
 fs/nfs/delegation.h               |  13 +++++
 fs/nfs/dir.c                      |  46 ++++++++++++----
 fs/nfs/inode.c                    |   3 ++
 fs/nfs/internal.h                 |   3 +-
 fs/nfs/localio.c                  |   4 +-
 fs/nfs/namespace.c                |  16 +++++-
 fs/nfs/nfs3proc.c                 |   3 +-
 fs/nfs/nfs4client.c               |  27 +++++++---
 fs/nfs/nfs4proc.c                 | 111 +++++++++++++++++++++++++++++++-------
 fs/nfs/nfs4trace.h                |   1 +
 fs/nfs/nfs4xdr.c                  | 106 ++++++++++++++++++++++++++++++++++++
 fs/nfs/pnfs.c                     |   1 +
 fs/nfs/proc.c                     |   3 +-
 fs/nfs/super.c                    |  33 ++----------
 fs/nfs/unlink.c                   |   3 +-
 include/linux/nfs_fs.h            |   1 +
 include/linux/nfs_fs_sb.h         |   6 +++
 include/linux/nfs_xdr.h           |  10 +++-
 include/linux/sunrpc/bc_xprt.h    |   7 +++
 net/sunrpc/backchannel_rqst.c     |  35 ++++++++++--
 net/sunrpc/xprtrdma/backchannel.c |   8 +--
 25 files changed, 385 insertions(+), 91 deletions(-)


-- 
Trond Myklebust
Linux NFS client maintainer, Hammerspace
trondmy@kernel.org, trond.myklebust@hammerspace.com

Re: [GIT PULL] Please pull NFS client updates for Linux 6.19

[pr-tracker-bot]

The pull request you sent on Thu, 11 Dec 2025 09:07:42 -0500:

> git://git.linux-nfs.org/projects/trondmy/linux-nfs.git tags/nfs-for-6.19-1

has been merged into torvalds/linux.git:
https://git.kernel.org/torvalds/c/6bb34aff1ebdd4ee8ea1721068f74d476d707f01

Thank you!

-- 
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/prtracker.html

NFS dentry caching regression? was Re: [GIT PULL] Please pull NFS client updates for Linux 6.19

[Christoph Hellwig]

Hi all,

the merge of this branch causes NFS lookup operation to shoot up a lot
for me.  And with merge I mean merge - both parent of the merge on their
own are fine.

With the script below that simulates running python scripts with lots
of imports that was created to benchmark delegation performance, the
number of lookups in the measurement period shoots up from 4 to about
410000, which is a bit suboptimal.  I have no idea how this could
happen, but it must be related to some sort of pathname lookup changes
I guess.  Other operations looks roughly the same.

---
#!/usr/bin/env bash
set -euo pipefail

if [ $# -ne 1 ]; then
    echo "Usage: $0 <NFS_MOUNT_PATH>"
    exit 1
fi

NFS_MOUNT="$1"
WARMUP_FILE_COUNT="8000"
RUNS=200
MODULE_COUNT=200
SAVEFILE="/tmp/nfsstat.bak"

echo "=== NFS delegation benchmark ==="
echo "NFS mount:          $NFS_MOUNT"
echo "Warmup file count:  $WARMUP_FILE_COUNT"
echo "Number of runs:     $RUNS"
echo "Module count:       $MODULE_COUNT"
echo


################################################################################
# Step 1: Create temporary directory on NFS
################################################################################
TEST_DIR=$(mktemp -d "$NFS_MOUNT/test_deleg_bench.XXXXXX")
MODULE_DIR="$TEST_DIR/pymods"
mkdir -p "$MODULE_DIR/delegtest"
MODDIR_INIT="$MODULE_DIR/delegtest/__init__.py"

cat > "$MODDIR_INIT" <<EOF
import os
import glob

file_paths = glob.glob(os.path.join(os.path.dirname(__file__), "*.py"))

__all__ = [
    os.path.basename(f)[:-3] 
    for f in file_paths 
    if os.path.isfile(f) and not f.endswith("__init__.py")
]
EOF

echo "[1] Creating $WARMUP_FILE_COUNT tiny files to accumulate delegations..."
mkdir -p "$TEST_DIR/fill"
for i in $(seq 1 "$WARMUP_FILE_COUNT"); do
    echo "f$i" > "$TEST_DIR/fill/file_$i"
done

echo "[1] Warmup delegation files created."

################################################################################
# Step 2: Create many tiny Python modules to exercise import workload
################################################################################
echo "[2] Creating $MODULE_COUNT dummy python modules..."
for i in $(seq 1 "$MODULE_COUNT"); do
    echo "x = $i" > "$MODULE_DIR/delegtest/mod$i.py"
done
#umount -o remount $NFS_MOUNT

# Python snippet:
# repeatedly import all modN modules; measure iterations completed
BENCH_SCRIPT="$TEST_DIR/bench.py"

cat > "$BENCH_SCRIPT" <<EOF
import sys

sys.path.insert(0, "$MODULE_DIR")

from delegtest import *
EOF

################################################################################
# Step 3: Pre-benchmark NFS client counters
################################################################################
echo "[3] Capturing baseline NFS client stats..."
sync $NFS_MOUNT
#mount -o remount $NFS_MOUNT
cp /proc/net/rpc/nfs $SAVEFILE

################################################################################
# Step 4: Run Python benchmark
################################################################################
echo "[4] Running Python import benchmark..."

time {
for i in $(seq 1 "$RUNS"); do
    python3 "$BENCH_SCRIPT"
done
}

################################################################################
# Step 5: Produce NFS client delta report
################################################################################
echo
echo "=== NFS client DELTA REPORT ==="
echo

nfsstat -c -S $SAVEFILE  -l
rm -f $SAVEFILE

echo
echo "Test directory:       $TEST_DIR"
echo
echo "=== Done ==="

Re: NFS dentry caching regression? was Re: [GIT PULL] Please pull NFS client updates for Linux 6.19

[Christoph Hellwig]

On Wed, Dec 17, 2025 at 01:32:30AM -0800, Christoph Hellwig wrote:
> Hi all,
> 
> the merge of this branch causes NFS lookup operation to shoot up a lot
> for me.  And with merge I mean merge - both parent of the merge on their
> own are fine.
> 
> With the script below that simulates running python scripts with lots
> of imports that was created to benchmark delegation performance, the
> number of lookups in the measurement period shoots up from 4 to about
> 410000, which is a bit suboptimal.  I have no idea how this could
> happen, but it must be related to some sort of pathname lookup changes
> I guess.  Other operations looks roughly the same.

To further pin this down, I rebased the patches from the NFS pull request
on top of the baseline (d358e5254674b70f34c847715ca509e46eb81e6f) and
bisected that.  This ends up in:

NFS: Shortcut lookup revalidations if we have a directory delegation

Re: [External] : Re: NFS dentry caching regression? was Re: [GIT PULL] Please pull NFS client updates for Linux 6.19

[Anna Schumaker]

Hi Christoph,

On 12/17/25 4:53 AM, Christoph Hellwig wrote:
> On Wed, Dec 17, 2025 at 01:32:30AM -0800, Christoph Hellwig wrote:
>> Hi all,
>>
>> the merge of this branch causes NFS lookup operation to shoot up a lot
>> for me.  And with merge I mean merge - both parent of the merge on their
>> own are fine.
>>
>> With the script below that simulates running python scripts with lots
>> of imports that was created to benchmark delegation performance, the
>> number of lookups in the measurement period shoots up from 4 to about
>> 410000, which is a bit suboptimal.  I have no idea how this could
>> happen, but it must be related to some sort of pathname lookup changes
>> I guess.  Other operations looks roughly the same.
> 
> To further pin this down, I rebased the patches from the NFS pull request
> on top of the baseline (d358e5254674b70f34c847715ca509e46eb81e6f) and
> bisected that.  This ends up in:

Thanks for reporting this, and for the reproducer script. I'll dig into this
today and try to fix what I broke!

Anna

> 
> NFS: Shortcut lookup revalidations if we have a directory delegation
> 

Re: [External] : Re: NFS dentry caching regression? was Re: [GIT PULL] Please pull NFS client updates for Linux 6.19

[Anna Schumaker]

Hi Christoph,

On 12/17/25 9:23 AM, Anna Schumaker wrote:
> Hi Christoph,
> 
> On 12/17/25 4:53 AM, Christoph Hellwig wrote:
>> On Wed, Dec 17, 2025 at 01:32:30AM -0800, Christoph Hellwig wrote:
>>> Hi all,
>>>
>>> the merge of this branch causes NFS lookup operation to shoot up a lot
>>> for me.  And with merge I mean merge - both parent of the merge on their
>>> own are fine.
>>>
>>> With the script below that simulates running python scripts with lots
>>> of imports that was created to benchmark delegation performance, the
>>> number of lookups in the measurement period shoots up from 4 to about
>>> 410000, which is a bit suboptimal.  I have no idea how this could
>>> happen, but it must be related to some sort of pathname lookup changes
>>> I guess.  Other operations looks roughly the same.
>>
>> To further pin this down, I rebased the patches from the NFS pull request
>> on top of the baseline (d358e5254674b70f34c847715ca509e46eb81e6f) and
>> bisected that.  This ends up in:
> 
> Thanks for reporting this, and for the reproducer script. I'll dig into this
> today and try to fix what I broke!
> 
> Anna

Does the following help? If so, then I'll probably split it up into a couple of
patches before sending to the list.

Thanks,
Anna

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index 23a78a742b61..c80f4d2289cd 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -1516,14 +1516,6 @@ static int nfs_check_verifier(struct inode *dir, struct dentry *dentry,
 	if (!nfs_dentry_verify_change(dir, dentry))
 		return 0;
 
-	/*
-	 * If we have a directory delegation then we don't need to revalidate
-	 * the directory. The delegation will either get recalled or we will
-	 * receive a notification when it changes.
-	 */
-	if (nfs_have_directory_delegation(dir))
-		return 0;
-
 	/* Revalidate nfsi->cache_change_attribute before we declare a match */
 	if (nfs_mapping_need_revalidate_inode(dir)) {
 		if (rcu_walk)
@@ -2216,13 +2208,6 @@ int nfs_atomic_open(struct inode *dir, struct dentry *dentry,
 }
 EXPORT_SYMBOL_GPL(nfs_atomic_open);
 
-static int
-nfs_lookup_revalidate_delegated_parent(struct inode *dir, struct dentry *dentry,
-				       struct inode *inode)
-{
-	return nfs_lookup_revalidate_done(dir, dentry, inode, 1);
-}
-
 static int
 nfs4_lookup_revalidate(struct inode *dir, const struct qstr *name,
 		       struct dentry *dentry, unsigned int flags)
@@ -2247,12 +2232,10 @@ nfs4_lookup_revalidate(struct inode *dir, const struct qstr *name,
 	if (inode == NULL)
 		goto full_reval;
 
-	if (nfs_verifier_is_delegated(dentry))
+	if (nfs_verifier_is_delegated(dentry) ||
+	    nfs_have_directory_delegation(dir))
 		return nfs_lookup_revalidate_delegated(dir, dentry, inode);
 
-	if (nfs_have_directory_delegation(dir))
-		return nfs_lookup_revalidate_delegated_parent(dir, dentry, inode);
-
 	/* NFS only supports OPEN on regular files */
 	if (!S_ISREG(inode->i_mode))
 		goto full_reval;
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index ec1ce593dea2..d74cd8659999 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -4830,7 +4830,6 @@ static int _nfs4_proc_access(struct inode *inode, struct nfs_access_entry *entry
 	int status = 0;
 
 	if (!nfs4_have_delegation(inode, FMODE_READ, 0)) {
-		nfs_request_directory_delegation(inode);
 		res.fattr = nfs_alloc_fattr();
 		if (res.fattr == NULL)
 			return -ENOMEM;
@@ -5422,6 +5421,10 @@ static int nfs4_proc_readdir(struct nfs_readdir_arg *arg,
 		.interruptible = true,
 	};
 	int err;
+
+	if (arg->plus)
+		nfs_request_directory_delegation(d_inode(arg->dentry));
+
 	do {
 		err = _nfs4_proc_readdir(arg, res);
 		trace_nfs4_readdir(d_inode(arg->dentry), err);


> 
>>
>> NFS: Shortcut lookup revalidations if we have a directory delegation
>>
> 
> 

Re: [External] : Re: NFS dentry caching regression? was Re: [GIT PULL] Please pull NFS client updates for Linux 6.19

[Christoph Hellwig]

On Wed, Dec 17, 2025 at 05:03:06PM -0500, Anna Schumaker wrote:
> Does the following help? If so, then I'll probably split it up into a couple of
> patches before sending to the list.

Yes, this fixed it.  Thanks for the quick response!